feat(文件归并): 归并PDF适配与解析逻辑

ofdgo_renderer_pdf_canvas.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 	"image"
 	"image/color"
+	"io"
 	"strconv"
 
 	"github.com/tdewolff/canvas"
@@ -150,6 +151,34 @@ func (r *pdfRenderer) glyphPath(path *canvas.Path, matrix canvas.Matrix) *canvas
 	return converted
 }
 
+// writePDF 传递后端资源记录及OFD导航修正，写出最终PDF
+// 入参: ctx 取消上下文, data 后端PDF数据, writer 输出流, optimization 优化配置
+// 返回: error 资源、压缩或写入错误
+func (r *pdfRenderer) writePDF(ctx context.Context, data []byte, writer io.Writer, optimization pdfgo.OptimizeOptions) error {
+	if r.imageError != nil {
+		return r.imageError
+	}
+	options := codecpdf.WriteOptions{
+		Images:       r.images,
+		Text:         r.text,
+		ExactImages:  r.exactImages,
+		ExactText:    r.exactText,
+		Optimization: optimization,
+	}
+	if r.navigation != nil && r.navigation.nativeWrite {
+		options.Links = make(map[int][]*pdfgo.LinkRegion, len(r.navigation.Link))
+		for page, links := range r.navigation.Link {
+			regions := make([]*pdfgo.LinkRegion, len(links))
+			for i, link := range links {
+				regions[i] = link.Region
+			}
+			options.Links[page] = regions
+		}
+		options.PrepareRewrite = r.navigation.prepareRewrite
+	}
+	return codecpdf.Write(ctx, data, writer, options)
+}
+
 // newPDFNavigation 建立文档导航与输出页索引，不读取页面图元
 // 入参: renderer 渲染器, doc 文档结构, pages 输出页面描述
 // 返回: *pdfNavigation 导航信息, error 资源或目标错误